There is one certainty on Memorial Day in Rohnert Park, and that is the annual Avenue of Flags ceremony at the RP Community Center, where once again Boy Scout troops will lead the parade to kick off the ceremonies. The annual event, in its 27th year, will feature the Community Band and a Color Guard procession, followed by this year’s guest speaker, William T. Grafe. Also, the Rohnert Park Chorale will perform. The event, based on past year’s attendances, is expected to draw a crowd of about 400 people. Also, 170 American flags are expected to be flown. The event runs from 9:30-11:30 a.m. The Community Center is located at 5401 Snyder Lane.